1. Field of the Invention
This invention relates to a detection process and a device for the injection system of a multicylinder engine, in particular of an automobile engine, making it possible to detect the speed of rotation of the engine, to perform permanently an angular pinpointing of the top dead center of each cylinder of the engine and an identification of the cylinder for which the injection of fuel is to take place.
2. Discussion of Background
Usually, the detection systems of the above-noted type include two targets in the form of ring gears mounted on the rotation shaft of the injection pump or of the engine, the targets working with two or three sensors to provide, on the one hand, the speed of rotation of the engine and the angular pinpointing of the top dead centers of the engine, and on the other hand, the identification of the cylinder in which the injection of fuel is to take place during the cycle of the engine.
Such detection systems are relatively bulky, costly and have a delicate mounting. Their principle of detection is generally based on a variation of a magnetic field created between the sensors and the ring gears of ferromagnetic material. When the speed of rotation of the engine is slow, the variation of the magnetic field is not significant enough to make possible a good measurement sensitivity. Furthermore, in the case where one of the sensors breaks down, i.e. in a mode of degraded operation of the engine, the standard measuring systems do not make it possible to provide enough data to the electronic injection control system of the engine, which causes the immediate stopping of the engine.